Protein translation, catalyzed by the ribosome, one of the most well- conserved macromolecular complexes, is a basic feature of all living organisms. Evidence has been accumulating that catalysis of peptide bond formation is mediated primarily by ribosomal RNA (rRNS), which provides a requisite catalytic core, known as the peptidyl transferase center (PTC), for this function. This proposal focuses on the tertiary structure of rRNA elements within the PTC that have been both genetically and biochemically implicated in the function of peptidyl transfer. NMR analysis in combination with molecular dynamics calculations will be utilized to derived solution structural models of RNA molecules from this domain. Length limits in NMR analysis of RNA molecules will also be investigated in this study, in particular through the use of deuterated RNA as a magnetically 'silent' context for a key RNA element. Comparison between structures of wild type PTC sequence and mutant sequences, known to compromise peptidyl transferase function, will allow identification of key structural elements, necessary for the biological activity of peptide bond formation.